Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

A dearth of intermediate melts at subduction zone volcanoes and the petrogenesis of arc andesites


Andesites represent a large proportion of the magmas erupted at continental arc volcanoes and are regarded as a major component in the formation of continental crust1. Andesite petrogenesis is therefore fundamental in terms of both volcanic hazard and differentiation of the Earth. Andesites typically contain a significant proportion of crystals showing disequilibrium petrographic characteristics indicative of mixing or mingling between silicic and mafic magmas, which fuels a long-standing debate regarding the significance of these processes in andesite petrogenesis2 and ultimately questions the abundance of true liquids with andesitic composition. Central to this debate is the distinction between liquids (or melts) and magmas, mixtures of liquids with crystals, which may or may not be co-genetic. With this distinction comes the realization that bulk-rock chemical analyses of petrologically complex andesites can lead to a blurred picture of the fundamental processes behind arc magmatism. Here we present an alternative view of andesite petrogenesis, based on a review of quenched glassy melt inclusions trapped in phenocrysts, whole-rock chemistry, and high-pressure and high-temperature experiments. We argue that true liquids of intermediate composition (59 to 66 wt% SiO2) are far less common in the sub-volcanic reservoirs of arc volcanoes than is suggested by the abundance of erupted magma within this compositional range. Effective mingling within upper crustal magmatic reservoirs obscures a compositional bimodality of melts ascending from the lower crust, and masks the fundamental role of silicic melts (≥66 wt% SiO2) beneath intermediate arc volcanoes. This alternative view resolves several puzzling aspects of arc volcanism and provides important clues to the integration of plutonic and volcanic records.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1: SiO 2 contents (H 2 O-free) of melt inclusions in arc magmas.
Figure 2: H 2 O–SiO 2 contents of melt inclusions from several arc volcanoes.
Figure 3: Comparison of chemical variation in melt inclusions, volcanic bulk rocks and experimental melts.
Figure 4: Experimental liquid lines of descent in temperature–composition space at a range of crustal pressures (100–700 MPa).
Figure 5: Chemical variation in melt inclusions, plutonic bulk rocks and experimental melts.


  1. Rudnick, R. L. Making continental crust. Nature 378, 571–578 (1995)

    Article  CAS  ADS  Google Scholar 

  2. Gill, J. B. Orogenic Andesites and Plate Tectonics (Springer, 1981)

    Book  Google Scholar 

  3. Naumov, B. V., Kovalenko, V. I., Babansky, A. D. & Tolstykh, M. L. Genesis of andesites: evidence from studies of melt inclusions in minerals. Petrology 5, 586–596 (1997)

    Google Scholar 

  4. Blundy, J. & Cashman, K. Rapid decompression-driven crystallization recorded by melt inclusions from Mount St. Helens volcano. Geology 33, 793–796 (2005)

    Article  CAS  ADS  Google Scholar 

  5. Wallace, P. J. Volatiles in subduction zone magmas: concentrations and fluxes based on melt inclusion and volcanic gas data. J. Volcanol. Geotherm. Res. 140, 217–240 (2005)

    Article  CAS  ADS  Google Scholar 

  6. Martin, V. M., Holness, M. B. & Pyle, D. M. Textural analysis of magmatic enclaves from the Kameni Islands, Santorini, Greece. J. Volcanol. Geotherm. Res. 154, 89–102 (2006)

    Article  CAS  ADS  Google Scholar 

  7. Naranjo, J. A., Sparks, R. S. J., Stasiuk, M. V., Moreno, H. & Ablay, G. J. Morphological, structural and textural variations in the 1988–1990 andesite lava of Lonquimay Volcano, Chile. Geol. Mag. 1†29, 657–678 (1992)

    Article  ADS  Google Scholar 

  8. Hildreth, W. Quaternary magmatism in the Cascades — geologic perspectives. Prof. Pap. US Geol. Surv. 1744, (2007)

  9. Grove, T. L., Donnelly-Nolan, J. M. & Housh, T. Magmatic processes that generated the rhyolite of Glass Mountain, Medicine Lake volcano, N California. Contrib. Mineral. Petrol. 127, 205–223 (1997)

    Article  CAS  ADS  Google Scholar 

  10. Muntener, O., Kelemen, P. B. & Grove, T. L. The role of H2O during crystallization of primitive arc magmas under uppermost mantle conditions and genesis of igneous pyroxenites: an experimental study. Contrib. Mineral. Petrol. 141, 643–658 (2001)

    Article  ADS  Google Scholar 

  11. Sisson, T. W., Ratajeski, K., Hankins, W. B. & Glazner, A. F. Voluminous granitic magmas from common basaltic sources. Contrib. Mineral. Petrol. 148, 635–661 (2005)

    Article  CAS  ADS  Google Scholar 

  12. Pichavant, M. & Macdonald, R. Crystallization of primitive basaltic magmas at crustal pressures and genesis of the calc-alkaline igneous suite: experimental evidence from St Vincent, Lesser Antilles arc. Contrib. Mineral. Petrol. 154, 535–558 (2007)

    Article  CAS  ADS  Google Scholar 

  13. Sisson, T. W. & Grove, T. L. Experimental investigations of the role of H2O in calc-alkaline differentiation and subduction zone magmatism. Contrib. Mineral. Petrol. 113, 143–166 (1993)

    Article  CAS  ADS  Google Scholar 

  14. Alonso-Perez, R., Muntener, O. & Ulmer, P. Igneous garnet and amphibole fractionation in the roots of island arcs: experimental constraints on andesitic liquids. Contrib. Mineral. Petrol. 157, 541–558 (2009)

    Article  CAS  ADS  Google Scholar 

  15. Depaolo, D. J., Perry, F. V. & Baldridge, W. S. Crustal versus mantle sources of granitic magmas — a 2-parameter model based on Nd isotopic studies. Trans. R. Soc. Edinb. 83, 439–446 (1992)

    CAS  Google Scholar 

  16. Hildreth, W. & Moorbath, S. Crustal contributions to arc magmatism in the Andes of central Chile. Contrib. Mineral. Petrol. 98, 455–489 (1988)

    Article  CAS  ADS  Google Scholar 

  17. Anderson, A. T. Magma mixing — petrological process and volcanological tool. J. Volcanol. Geotherm. Res. 1, 3–33 (1976)

    Article  CAS  ADS  Google Scholar 

  18. Reubi, O. & Blundy, J. Assimilation of plutonic roots, formation of high-K exotic melt inclusions and genesis of andesitic magmas at Volcán de Colima, Mexico. J. Petrol. 49, 2221–2243 (2008)

    Article  CAS  ADS  Google Scholar 

  19. Dungan, M. A. & Davidson, J. Partial assimilative recycling of the mafic plutonic roots of arc volcanoes: an example from the Chilean Andes. Geology 32, 773–776 (2004)

    Article  CAS  ADS  Google Scholar 

  20. Chappell, B. W. & White, A. J. R. Two contrasting granite types: 25 years later. Aust. J. Earth Sci. 48, 489–499 (2001)

    Article  CAS  ADS  Google Scholar 

  21. Annen, C., Blundy, J. D. & Sparks, R. S. J. The genesis of intermediate and silicic magmas in deep crustal hot zones. J. Petrol. 47, 505–539 (2006)

    Article  CAS  Google Scholar 

  22. Grove, T. L. & Donnelly-Nolan, J. M. The evolution of young silicic lavas at Medicine Lake Volcano, California — implications for the origin of compositional gaps in calc-alkaline series lavas. Contrib. Mineral. Petrol. 92, 281–302 (1986)

    Article  CAS  ADS  Google Scholar 

  23. Arculus, R. J. in State of the Arc Conference Extended Abstracts and Programme (eds Dungan, M. A., Grunder, A., Hickey-Vargas, R., Moreno Roa, H. & Muňoz, J.) 1–4 (IAVCEI, 2007)

    Google Scholar 

  24. Wright, I. C. & Gamble, J. A. Southern Kermadec submarine caldera arc volcanoes (SW Pacific): caldera formation by effusive and pyroclastic eruption. Mar. Geol. 161, 207–227 (1999)

    Article  CAS  ADS  Google Scholar 

  25. Glazner, A. F., Bartley, J. M. & Coleman, D. S. in State of the Arc Conference Extended Abstracts and Programme (eds Dungan, M. A., Grunder, A., Hickey-Vargas, R., Moreno Roa, H. & Muňoz, J.) 79–80 (IAVCEI, 2007)

    Google Scholar 

  26. Ulmer, P. Differentiation of mantle-derived calc-alkaline magmas at mid to lower crustal levels: experimental and petrologic constraints. Period. Mineral. 76, 309–325 (2007)

    Google Scholar 

  27. Blundy, J. D. & Sparks, R. S. J. Petrogenesis of mafic inclusions in granitoids of the Adamello Massif, Italy. J. Petrol. 33, 1039–1104 (1992)

    Article  CAS  ADS  Google Scholar 

  28. Blundy, J., Cashman, K. & Humphreys, M. Magma heating by decompression-driven crystallization beneath andesite volcanoes. Nature 443, 76–80 (2006)

    Article  CAS  ADS  Google Scholar 

  29. Humphreys, M. C. S., Blundy, J. D. & Sparks, R. S. J. Shallow-level decompression crystallisation and deep magma supply at Shiveluch Volcano. Contrib. Mineral. Petrol. 155, 45–61 (2008)

    Article  CAS  ADS  Google Scholar 

  30. Johnson, E. R., Wallace, P. J., Cashman, K. V., Granados, H. D. & Kent, A. J. R. Magmatic volatile contents and degassing-induced crystallization at Volcán Jorullo, Mexico: implications for melt evolution and the plumbing systems of monogenetic volcanoes. Earth Planet. Sci. Lett. 269, 477–486 (2008)

    Article  CAS  ADS  Google Scholar 

  31. Roggensack, K. Unraveling the 1974 eruption of Fuego volcano (Guatemala) with small crystals and their young melt inclusions. Geology 29, 911–914 (2001)

    Article  CAS  ADS  Google Scholar 

  32. Roedder, E. Fluid Inclusions (Mineralogical Society of America, 1984)

    Book  Google Scholar 

  33. Danyushevsky, L. V., Della-Pasqua, F. N. & Sokolov, S. Re-equilibration of melt inclusions trapped by magnesian olivine phenocrysts from subduction-related magmas: petrological implications. Contrib. Mineral. Petrol. 138, 68–83 (2000)

    Article  CAS  ADS  Google Scholar 

  34. Danyushevsky, L. V., McNeill, A. W. & Sobolev, A. V. Experimental and petrological studies of melt inclusions in phenocrysts from mantle-derived magmas: an overview of techniques, advantages and complications. Chem. Geol. 183, 5–24 (2002)

    Article  CAS  ADS  Google Scholar 

  35. Cottrell, E., Spiegelman, M. & Langmuir, C. H. Consequences of diffusive reequilibration for the interpretation of melt inclusions. Geochem. Geophys. Geosyst. 3, 1–26 (2002)

    Article  Google Scholar 

  36. Humphreys, M. C. S., Blundy, J. D. & Sparks, R. S. J. Magma evolution and open-system processes at Shiveluch Volcano: insights from phenocryst zoning. J. Petrol. 47, 2303–2334 (2006)

    Article  CAS  ADS  Google Scholar 

  37. Danyushevsky, L. V., Leslie, R. A. J., Crawford, A. J. & Durance, P. Melt inclusions in primitive olivine phenocrysts: the role of localized reaction processes in the origin of anomalous compositions. J. Petrol. 45, 2531–2553 (2004)

    Article  CAS  ADS  Google Scholar 

Download references


This work was supported by a Marie Curie Fellowship (O.R.) and an NERC Senior Research Fellowship (J.B.). We thank S. Sparks, K. Kelley and K. Roggensack for comments on an early draft of this manuscript, and P. Wallace and M. Pichavant for critical reviews. We are grateful to V. C. Smith for unpublished data and discussions.

Author Contributions O.R. and J.B. developed the discussion. O.R. took the lead in writing the paper.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Olivier Reubi.

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Reubi, O., Blundy, J. A dearth of intermediate melts at subduction zone volcanoes and the petrogenesis of arc andesites . Nature 461, 1269–1273 (2009).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing